import java.util.*;
class Example2_5{
   public static void main(String args[]){
     int start=0,end,middle;
     int a[]={12,45,5319,67,89,123,-45,67};
     int N=a.length;
     for(int i=0;i<N;i++){
     for(int j=i+1;j<N;j++){
        if(a[j]<a[i]){
          int t=a[j];
          a[j]=a[i];
          a[i]=t;
       }
     }
   }

Scanner scanner =new Scanner(System.in);
System.out.println("请输入整数，程序判断该整数是否存在数组中:");
int number=scanner.nextInt();
int count=0;
end=N;
middle=(start+end)/2;
while(number!=a[middle]){
if(number>a[middle])
start=middle;
else if(number<a[middle])
end=middle;
middle=(start+end)/2;
count++;
if(count>N/2)
break;
}
if(count>N/2)
System.out.printf("%d不在数组中.\n",number);
else
System.out.printf("%d在数组中.\n",number);
}
}

